Electrical relay



Aug. 9, 1938. w. L. STOUT 2,126,674-

ELECTRICAL RELAY Filed OCT 18, 1935v 2 Sheets-Sheet l H15 TTORNE Augu 9, 1938. w STQUT 2,126,674

' ELECTRICAL RELAY Filed Oct. 18, 1935 2 Sheets-Sheet 2 a 5a 5* a INVEN'TOR 1 WzZtarL. Stout.

HIS ATTORN EY Patented Aug. 9, 1938 ELECTRICAL RELAY Walter L. Stout, Edgewood, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa.I a corporation of Pennsylvania Application October 18, 1935, Serial No. 45,615

6 Claims.

v invention relates to electrical relays and the lilre, and particularly to detachable terminal plates for such devices.

One object of my invention is to provide a detachable terminal plate-which may be quickly secured to, or detached from, the usual top plate of a relay, and which when secured to the top plate will automatically eflect the proper external circuit connections with the relay, thus making it possible to replace a relay which is in service with another similar relay without causing delays in the operation of the system of which the relay forms a part.

Another object of my invention is to provide 16 a detachable terminal plate of the type described which requires a minimum number of parts, and which can be manufactured at a minimum cost.

I will describe two forms of relays embodying my invention, and will then point out the novel 20 features thereof in claims.

in the accompanying drawings, Fig. l is a view partly in section and partly in elevation, showing one form of detachable terminal plate embodying my invention mounted on a relay top 35 plate. Fig. 2 is a top plan view of the top plate 13 shown in Fig. i. Fig. 3 is a bottom view of the detachable terminal plate shown in Fig. 1. Figs. '4 and 5 are detail views showing a modification oi a portion of the terminal plate shown in Figs.

30 l, i and 3. Fig. ii is a view similar to Fig. 1 showing a modified form oi? the detachable terminal plate illustrated in Fig. l.

Slur reference characters refer to similar parts in each of the several views.

35 Reierring first to Figs. 1 to 3, inclusive, the reierenoe character A designates the usual top plate of an electrical control device such for example as an electrical relay, and the reference character i designates a suitable casing which is 40 secured to the top plate A and which houses the operating and contact mechanisms (not shown) oi the relay. Mounted on the top plate A in the usual manner are a plurality of terminal posts 2 cl standard construction, through the medium of 45 which external electrical connections with the operating and contact mechanisms of the relay are adapted to be made.

Associated with the top plate A is a detachable terminal plate B embodying my present invention.

50 This terminal plate, which is of insulating material, is adapted to be disposed above the top plate A in axial alignment therewith, and is provided at its outer edge with a depending annular flange t which supports the terminal plate in is spaced parallel relation with respect to the top plate, the parts preferably being so proportioned that the diameter of the terminal plate is slightly smaller than the diameter of the top plate. Mounted on the terminal plate are a plurality of terminal posts 4. These-terminal posts are 5 similar in construction to the terminal posts 2 and each aligns vertically with a different one of the terminal posts 2, as many terminal posts 4 being provided as there are terminal posts 2. Secured to each terminal post 4 on the under side 10 of the terminal plate B is a contact member 5,- the upper end of which fits in a recess 6 provided in the under side of the terminal plate B, and: cooperates with the head of the associated terminal post 4 in such manner that both the terminal post and the contact member are prevented from turning. Each contact member 5 is provided with 'a plurality of depending flexible contact fingers ii (preferably three or more) which contact fingers are biased toward each other by their own resiliency, and which are so shaped that each of these fingers will engage anassociated one of the terminal posts 2 with a relatively large contact area. The fingers 5 are each bent outwardly at their lower ends in the manner shown for a purpose presently to be described. Each terminal post 4 is provided with the usual clamping nuts 4 and also with an insulating nut l which. covers the upper end of the terminal post. The function of the insulating nuts I is to prevent short circuits due to metal objects coming in contact with two or more of the terminal posts or vice versa.

A wedging plate 8, which is also of insulating material, is mounted for vertical sliding movement within the flange 3 of the terminal plate B, and is provided with a plurality of vertically disposed holes 9, one of which surrounds the fingers 5 of each contact member 5 in the manner shown. The lower ends of the holes 9 are enlarged to receive the clamping nuts I 0 which are provided on the terminal posts 2 to secure these terminal posts to the top plate A, and these holes are provided at the junctions of their enlarged lower portions and the upper portions with a tapered connecting portion which cooperates with the outwardly bent lower portions of the fingers in such manner that when no downward force is exerted on the wedging plate relative to the terminal plate, the resiliency of the contact fingers will force the wedging plate upwardly to a position in which the wedging plate exerts very little, if any, force on the contact fingers, but that, if the wedging plate is forced downwardly relative to the terminal plate, the tapered portions of. the holes 9 will cooperate minal posts.

with the outwardly bent portions of the fingers I to force the fingers inwardly, and will thus cause the fingers to be clamped into engagement with the terminal posts 2 in a manner to make good electrical and mechanical contact with the terminal posts. The wedging Plate I may be forced downwardly relative to the terminal plate by any suitable means such, for example, as a plurality of thumb screws ll, screwed through threaded bushings It molded in the terminal plate '8, and engaging the upper sides of the wedging plate. The thumb screws may be locked in any desired position by means of lock nuts l2.

. In applying a top plate of the type described to a relay for the first time, all nuts and washers which are usually provided on the terminal posts 2 with the exception of the'nuts II and washers shown are first removed from the terminal posts 2 of the relay, and if the relay has already been in service, all circuit wires are also removed from the terminal posts. Each circuit wire is then attached to the terminal post 4 of the detachable terminal plate 13 corresponding to the terminal post 2 of the relay to which such wire was previously connected or would be connected if the detachable terminal plate were not provided. The thumb screws II are next backed out far enough to insure that all tension due to the wedging plate is removed from the fingers 5 of the contact members 5, and the terminal plate is then placed in the Proper axial alignment with the top plate A and forced downwardly to the position in which the flange 2 engages the upper side of the top plate A, thus causing the contact fingers I to engage the associated terminal posts 2 of the relay. The wedging plate I is next forced downwardly by means of the thumb screws ii to the position in which it is shown in the drawings, thus causing the tapered portions of the lples t to engage the outwardly bent lower ends of the fingers and force the fingers inwardly in the manner previously described to provide good electrical and mechanical contact with the ter- When a relay has been provided with a removable terminal plate of the type described, and it is subsequently desired to remove the relay from service, the thumb screws are first backed out far enough to permit the wedging plate to move upwardly and remove the tension from the fingers I of the contact members. The terminal plate is then lifted bodily oil of the top plate of the relay and placed on' the top plate of the replacement relay, after which the wedging plate is again forced downwardly to the position shown in the drawings by means of the thumb screws II. The lock n'uts l2 are then tightened and the replacement relay is ready for service.

Under some conditions it may be desirable to force the wedging. plate downwardly to such a position that the lower ends of the fingers i will no longer be effective to raisethe wedging plate when the thumb screws ii are backed out, and when this is the case, the thumb screws It may be anchored at their lower ends in the wedging plate 8 in the manner shown in Figs. 4 and 5. With this latter arrangement, it will be apparent that the wedging plate is compelled to move vertically with the thumb screws, but that the thumb screws arefree to rotate relative to the wedging plate.

It should be particularly pointed out that with the detachable terminal plate constructed in the manner described, if the wedging plate is forced downwardly to the position shown in the drawings and a contact finger 5'} should break, the broken finger will be prevented from falling out of the associated hole 8, thus precluding the possibility of a broken finger causing undesirable short circuits.

Referring now to Fig. 6, the terminal plate here shown is similar to that shown in the preceding views with the exception that the wedging plate I has been turned upside down, and that the contact members I have been replaced by contact members ll having depending contact fingers II the lower ends of which are provided with inwardly bent portions which cooperate with the tapered portions of the holes 8 in the wedging plate in such manner that movement of the wedging plate toward the terminal plate will force the fingers I into engagement with the associated terminal posts 2 on the relay top plate A rather than movement of the wedging plate away from the terminal plate. The operation of the structure shown in Fig. 6 will be apparent from the foregoing and from an inspection of the drawings without further description.

One advantage of a terminal plate embodying my invention is that a minimum number of parts are required all of which are easy to manufacture.

A further advantage of a terminal plate embodying my invention is that the contact members I and II can be so constructed that the contact fingers will engage a maximum amount of the surface of the terminal posts 2, thus insuring a reliable contact with the terminal posts,

A still further advantage of a terminal plate embodying my invention is that only one wedging plate is required which permits the top plate to be constructed with a minimum overall height.

Although I- have herein shown and described only one form of detachable terminal plate embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. The combination with an electrical relay provided with a top plate having a plurality of terminal posts mounted thereon for making electrical connection with the operating and contact mechanisms of the relay, of a detachable terminal plate of insulating material having mounted thereon a plurality of terminal posts one of which aligns with each terminal post on said top plate, a plurality of contact members secured to the terminal posts on said terminal plate on one side of said terminal plate, each said contact member being provided with a plurality of contact fingers which are adapted to engage the associated terminal post on said top plate, a wedging plate secured to said terminal plate for movement toward and away from said terminal plate, means for moving said wedging plate, and means responsive to movement of said wedging plate away from said top plate for securely clamping said contact fingers into engagement with the associated terminal posts on said top plate.

2. The combination with an electrical device provided with a top plate having a plurality of terminal posts mounted thereon for making external electrical connections with the device, of a detachable terminal'plate of insulating material having mounted thereon a plurality of terminal posts one of which aligns with each terminal post on said top plate, a plurality of contact members one secured to each terminal post on said terminal plate and each provided with a plurality of contact fingers which are biased toward each other by their own resiliency and which are adapted to engage the aligned terminal post on said\top plate, each said contact finger being provided at its free end with an outwardly bent portion, an insulating wedging plate movable toward and away from said terminal plate and provided with a plurality of holes one of which surrounds the contact fingers of each contact member and each of which is provided with a tapered portion which cooperates with the outwardly bent portions of the fingers to force the fingers into engagement with the terminal posts on said top plate when the wedging plate is moved away from said terminal plate, and means on said terminal plate for moving said wedging plate toward and away from said terminal plate.

3. The combination with an electrical device provided with a top plate having a plurality oi terminal posts mounted thereon for making external electrical connections with the device, of a detachable terminal plate of insulating material having mounted thereon a plurality oi terminal posts one of which aligns with each terminal post on said top plate, a plurality of contact members one secured to each terminal post on said terminal plate and each provided with a plurality of contact fingers which are biased toward each other by their own resiliency and which are adapted to engage the aligned terminal post on said top plate, each said contact finger being provided at its tree end with an outwardly bent portion, an insulating wedging plate movable toward and away from said terminal plate and provided with a plurality of holes one of which surrounds the contact fingers of each contact member. and each of which is provided with a tapered portion which cooperates with the outwardly bent portion of the fingers to force the fingers into engagement with the terminal posts on. said top plate when said wedging plate is moved away from said terminal plate, and a plurality of thumb screws screwed through said terminal plate and anchored at their lower ends in said wedging plate.

4. The combination with an electrical device provided with a top plate having a plurality of terminal posts mounted thereon for making external electrical connections with the device, 01 a detachable terminal plate of insulating material having mounted thereon a plurality oi terminal posts one oi! which aligns with each terminal post on said top plate, a plurality of contact members one secured to each terminal post on said terminal plate and each provided with a plurality of contact fingers which are biased toward each other by their own resiliency and which are adapted to engage the aligned terminal post on said top plate, each said contact finger being provided adjacent its free end with an inwardly bent portion, an insulating wedging plate movable toward and away from said terminal plate and provided with a plurality of holes one of which surrounds the contact fingers of each contact member and each of which is provided with a tapered portion which cooperates with the inwardly bent portion of the fingers to force the fingers into engagement with the terminal posts on said top plate when the wedging plate is moved toward said terminal plate, and 5 means on said terminal plate for moving said wedging plate toward said terminal plate.

5. The combination with an electrical device provided with a top plate having a plurality of terminal posts mounted thereon for making external electrical connections with the device, of a detachable terminal plate of insulating ma terial having mounted thereon a plurality of terminal 'posts one of which aligns with each terminal post on said top'plate, a plurality of contact members one secured to each terminal post on said terminal plate and each provided with a plurality of contact fingers which are biased toward each other by their own resiliency and which are adapted to engage the aligned terminal post on said top plate, each said contact finger being provided adjacent its free end with an inwardly bent portion, an insulating wedging plate movable toward and away from said terminal plate and provided with a plurality of holes one of which surrounds the contact fingers of each contact member and each of which is provided with a tapered portion which cooperates with the inwardly bent portions of the fingers to force the fingers into engagement with the terminal posts on said top plate when the wedging plate is moved toward said terminal plate, and a plurality of thumb screws screwed through said terminal plate and anchored at their lower ends in said wedging plate.

6. The combination with an electrical device having a. top plate provided with projecting terminal posts for making external electrical connections with the device, of a detachable terminal plate of insulating material having mounted thereon a plurality of terminal posts one of which aligns with each terminal post on said top plate, said terminal plate being provided at its outer edge with an annular flange which rests on said top plate and which supports said terminal plate in fixed spaced parallel relation with respect to said top plate, a plurality of contact members one secured to each terminal post on said terminal plate and each provided with a plurality of contact fingers which are biased toward each other by their own resiliency and which are adapted to engage the aligned terminal post on said top plate, each said contact finger being provided with an outwardly bent portion, a wedging plate slidabiy mounted within said flange ior axial movement between two positions relative to said terminal plate and provided with a plurality 01 holes one of which surrounds the contact fingers of each contact member and each of which is provided with a tapered portion which cooperates with the outwardly bent portion of the fingers in such manner that said wedging plate is normally biased by the fingers to one position but becomes eflective when moved to its other position to force the fingers into engagement with the terminal posts on said top plate, and means including a plurality of thumb screws for moving said wedging plate from its one position to its other position.

WALTER L. STOUT. 

